Improvement in firemen s ladders



SSheets--SheetL P; PORTA. Fivremens Ladders.

No, 142,349, atented September-2, 187:3.

' m VENTOR 3 Sheets--Sheet 2'. P. P0 BT Firemens Ladders.

N0. 142,349. PatentedSeptembr2,1873.

UNITED STATES PAOLO PORTA, O F MILAN, ITALY, ASSIGNOB TO MIGHELO UDA/ AND MARY l B. S. UDA, OF SAME PLAGE.

IMPROVEMENT IN-FIREMENS LADDERS.-

Specification forming part of Letters Patent No. 142,349, dated September 2, 1873 application filed March 13, 1873. Y

To allwhom fit may concern Be it known that I, PAOLO PORTA, of Milan, Kingdom of Italy, have invented a system of Aerial, Flying, and Bridge Ladders; and Ido hereby declare that the following is a full, clear, and exact description of the construction and operation of the same, reference being had to the annexed drawings making a part of this specification.

My invention relates toa class of ladders which I term Aerial Ladders,'7 in contradis tinction to such ladders as require to be supported against a building; and consists of a combination of devices and appliances, as hereinafter set forth, consisting of a suitable truck, to which is attached the lower sectionv of a ladder, and carrying at the same time the other sections of the same-the whole so adjusted and arranged, in connection with suitable mechanism, that the ladder can be raised and supported at any desired angle without -connection with anything save to its supportingtruck, as will appear in the following description. v

In the drawings, Figure 1, Sheet 1, is a side elevation of three sections of the ladder, and asafetysack suspendedfrom the upper section; the ladders have been taken from the truck, adjusted, and raised. Fig. 2, Sheet 2, is a vertical section, showing parts in elevation taken longitudinally through the truck. Fig. 3, Sheet 1, is a view of the top section, provided with braces 'upon both sides of same. Fig. 4, Sheet 2, is a view of the mechanism for joining the sections. Fig. 5 shows the tiebar completing the joint and forming a step of the ladder. Fig.6 shows sections of the brace-rods. Fig. 7 represents the truck with the lower section shipped and another section about to be placed on the truck.

A is the bed of the truck, and just in front of the rear axle, at l, is pivoted the lower section B of the latter.- This section B has a lever-arm, B', projecting from the pivot b at an angle toward the rear, which bars the l roller C at its extremity. A shaft or roller, D, just in front of the pivot b, is provided with a large gear-wheel, C', which engages with the pinion D' on the end of the crank-shaft D".

Cords E are attached to the roller D, which pass down beneath a roller, F, attached to the lower end of a descending brace, F', at the rear of the truck, thence up over the roller C and down again to the bottom of the brace F', where they are secured. vThe truck, when ready for use, is provided with the entire ladder in sections, piled upon it as represented in Fig. 7 ,Plate 3,together with the brace-rods, &c. When necessary to put the device to use, the sections are all removed and properly attached in regular order to the lower section B, the brace-rods adj usted, and, all beingin readiness, the ladder is raised by turning the crank-4 shaft D" 5 this winds the cords E upon the shaft or roller D, and, by shortening the distance between rollers C and F, brings the lever-arm B' down and carries the ladder up. To counteract any tendency to tip forward, the truck is provided with sliding counterpoise-weights G, which are slid out before the ladder is raised. When raised, as shown in Fig. 1, Sheet 1, the brace-rods K K' K" K"' L, with their intermediate posts L', form a rigid and steady truss-support. 'This support may be rendered still more effective by adding a similar set of brace-rods to the upper sections on the under side of the ladders, as shown in Fig. 3, Sheet 1. This addition, however, is not absolutely necessary.

The construction of the various parts will he readily understood by reference to the drawings.

In Fig. 3, Sheet 1, is shown a device for bracing the top section of the ladder. The cross-piece L' is made to project beyond the ladder on both sides, and is provided at lits ends, on both sides, with spurs j. The eyes at the ends of the straining-rods are slipped upon these spurs, and the whole secured in place by the keys j", or by any other suitable means.

The additional posts L' are situated at or near the ends of each section of the ladder, and a straining-rod, K, extends from the exterior end of each to the base of the next succeeding one, while a tie-rod, K', in sections, unites the ends of all. The lever-arm B' of the base section is strongly secured to the upright B by the straining-rods or bars K" K'" and L.

It will be seen that the strains are all strains of extension, except those upon the posts and upon the ladders, which in both instances are longitudinal strains of compression. rlhe strains are, therefore, all communicated directly to the base section, and all tendency to sag is avoided, and the materials subjected to those strains which they are most capable of supporting.

In Figs. 4 and 5 are shown the jointing devices. The ends of the ladder sections are provided with strap-loops b', and halved so as to fit upon each other and permit the key-bar M to be inserted. Other methods of uniting the sections and the tie-rods may be employed, but the devices shown are simple and effective.

In Fig. 6 are sectional views of the straining and tie rods K K', &c., and which are hollow and diminish in size from the base to the top section of the ladder in proportion as the strain is diminished.

The truck is provided with suitable running-gear and with suitable brakes to fix the carriage rigidly in plaee when desired.

l. In combination with a truck, A, a pivoted ladder, B, provided with a rigid angular lever arm, B'-the lever-arm B' connected by a suitable cord to a crank-gearin g, C D, attached to the truck-by means of which the ladder may be raised, lowered, or secured at any desired inclination, all substantially as set forth and shown.

2. In combination with a ladder, the bracing and self-sustaining system, substantially as set forth, of uprights L', tie-rods K joining the top ends of the uprights, and the diagonal straining-rods K K", 85e., joining the upper end of each post With the base of the adjacent one successively from the base to the top of the ladder.

3. For fastening the rods to the posts L', the spurs j and pins or keys j", substantially as set forth and shown.

4. In combination with a truck and self-supporting ladder, counterpoise-Weights G suitably adjusted, as set forth, for changing the position of the center of gravity, substantially as described.

5. 'lhe ladder-joint composed of the straploops b halved into each other, and the flattened key-rung M, the latter forming the bearing of the ladder-frame, substantially as set forth and shown.

Given in Milan, February 6, 1873. h

PAOLO PORTA.

Witnesses:

DeMENIoo TRoJA, OSCAR GoooRDA. 

